Osteosclerosis, a recessive skeletal mutation on chromosome 19 in the mouse

Osteosclerosis (oc) is an osteopetrotic mutation in the mouse inherited as an autosomal recessive on chromosome 19. Affected animals (oc/oc) exhibit the characteristic radiologic and histologic hallmarks of osteopetrosis including a generalized increase in skeletal density and absence of marrow cavities. Most die within three weeks after birth. Osteoclasts are cytologically abnormal by light microscopy in that they do not have cytoplasmic vacuoles. Presumptive evidence of rickets in this mutation includes thick cartilagenous growth plates and excessive osteoid. Extensive extramedullary hemopoiesis occurs in the liver and spleen of mutants. This unique constellation of features suggests that the oc mutation is a valuable model in which to investigate the pathogenesis of osteopetrosis.